[patch 08/12] entryval#3: lval_funcs->{read,write} can be now NULL

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

Hi,

unchanged:
	[patch 08/12] entryval#2: lval_funcs->{read,write} can be now NULL
	http://sourceware.org/ml/gdb-patches/2011-09/msg00230.html


Thanks,
Jan


gdb/
2011-07-18  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Make some lval_funcs methods to default on NULL.
	* valops.c (value_fetch_lazy): Check if lval_computed read method is
	NULL.
	(value_assign): Check if lval_computed write method is NULL.
	* value.h (struct lval_funcs): Comment NULL values for read and write
	methods.

--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -1110,7 +1110,8 @@ value_fetch_lazy (struct value *val)
 	 watchpoints from trying to watch the saved frame pointer.  */
       value_free_to_mark (mark);
     }
-  else if (VALUE_LVAL (val) == lval_computed)
+  else if (VALUE_LVAL (val) == lval_computed
+	   && value_computed_funcs (val)->read != NULL)
     value_computed_funcs (val)->read (val);
   else if (value_optimized_out (val))
     /* Keep it optimized out.  */;
@@ -1381,9 +1382,13 @@ value_assign (struct value *toval, struct value *fromval)
       {
 	const struct lval_funcs *funcs = value_computed_funcs (toval);
 
-	funcs->write (toval, fromval);
+	if (funcs->write != NULL)
+	  {
+	    funcs->write (toval, fromval);
+	    break;
+	  }
       }
-      break;
+      /* Fall through.  */
 
     default:
       error (_("Left operand of assignment is not an lvalue."));
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -156,13 +156,15 @@ struct lval_funcs
 {
   /* Fill in VALUE's contents.  This is used to "un-lazy" values.  If
      a problem arises in obtaining VALUE's bits, this function should
-     call 'error'.  */
+     call 'error'.  If it is NULL value_fetch_lazy on "un-lazy"
+     non-optimized-out value is an internal error.  */
   void (*read) (struct value *v);
 
   /* Handle an assignment TOVAL = FROMVAL by writing the value of
      FROMVAL to TOVAL's location.  The contents of TOVAL have not yet
      been updated.  If a problem arises in doing so, this function
-     should call 'error'.  */
+     should call 'error'.  If it is NULL such TOVAL assignment is an error as
+     TOVAL is not considered as an lvalue.  */
   void (*write) (struct value *toval, struct value *fromval);
 
   /* Check the validity of some bits in VALUE.  This should return 1